Rohan Singh (anonymous)

sir, according to the third rule you have said that n=3 shell cannot hold more than 8 electrons but cobalt(Co) atomic no 27,k shell-2 electrons, L shell-8 electrons m shell-15 electrons, n shell-2 electrons, why not m shell-8 electrons and n shell-9 electrons or m shell-16 electrons and n shell-1 electrons. Explain.